The Czechs improved their Davis Cup doubles record to 12-1 by converting their third match point in front of more than 13,000 fans at the O2 Arena, who blew trumpets, beat drums and cheered loudly between points.

"It's incredible," said Berdych who closed out the match with an overhead volley.

"It's just one point (missing). We'll do everything for that."

The sixth-ranked Berdych can clinch the best-of-five series in the first reverse singles on Sunday with a victory over David Ferrer.

"We're leading 2-1, that's the best possible score we could get on Saturday. That gives us a lot of extra energy"

Czech Tomas Berdych

"It's still a long way to go but we're in a better position than them," Berdych said.

"We're leading 2-1, that's the best possible score we could get on Saturday. That gives us a lot of extra energy."

Ferrer, who is wrapping up the best season of his career having won a tour-best seven tournament titles, has a 5-3 career record against Berdych.

Stepanek takes on Nicolas Almagro in the final match.

"It will be as difficult for us as for them,'' Spain captain Alex Corretja said.

"We need to win both. We cannot make a mistake."

Ferrer was training on Saturday while Berdych had to spend three and a half hours on the court after another four hours on Friday.

"For the moment, they're very tired, but they're 2-1," Corretja said.

While Spain have double specialists in Lopez and Granollers, the Czechs fully rely on Berdych and Stepanek, who are used to playing three matches in three days in Davis Cup.

"I'm ready to do it tomorrow," Berdych said.

"I'll try to come with my strong game, and with the crowd on my back it would be a good combination to make it."

The Czechs are seeking to complete a rare double just two weeks after the women secured the Fed Cup title in the same arena. No country has won both competitions in the same year since the United States in 1990.

Spain are looking for their fourth title in five years, while the Czechs' only victory came in 1980 as Czechoslovakia, which split in 1993.